Several determinations of the dose-response effects of alcohol on human aggressive behavior will be completed under varying environmental conditions in a laboratory setting. In this setting, single variables will be manipulated to isolate critical dimensions of the environment that increase the risk of untoward alcohol effects on aggressive behavior. In an isolated room, subjects are provided unrestricted access to two response levers. Responding on the first lever produces points as determined by operant schedules of reinforcement. These points are exchanged for money following each session. Responding on the second lever ostensibly subtracts a point (removes money) from a fictitious research subject also depicted as participating in a research project at some other location. Agressive behavior has been operationally defined by laboratory investigators as behavior that presents a noxious or aversive stimulus to another individual. Previous research has shown that point subtractions function as aversive stimuli for human subjects. As such, responses on the second lever represent an operationally defined, objective measure of aggressive behavior. Subjects are told prior to the experiment that the research subject paired with them may also respond on a lever to subtract their points. Probabilities of aggressive behavior are controlled by occasional point subtractions that are attributed to the other person. This procedure yields aggressive behavior that is stable over time within subjects and unconstrained by experimental trials. Most sessions last approximately fifty minutes. Six situational variables will be manipulated to determine their modulating effects on alcohol-aggressive behavior interactions. These variables were selected because of their direct effects on human aggressive behavior and because of their relevance to drug effects on human behavior in general. First, the frequency and intensity of provocation will be manipulated. Second, the consequences maintaining aggressive behavior will be evaluated. Third, escape and eliciting variables maintaining aggressive responding will be explicitly separated using a three-response option. Fourth, the effects of concurrent reinforcement (adjunctive) schedules on aggressive behavior will be measured. Fifth, the temporal parameters of alcohol consumption will be manipulated to determine whether alcohol effects vary as a function of increasing or decreasing systemic alcohol levels. Finally, experience with alcohol will be evaulated by comparing groups of subjects differing only in the extent of their tolerance to the behaviorally-intoxicating effects of alcohol.